Abstract： Objective To inquire into interleukin-10(IL-10)level and monocyte expression of human leukocyte antigen-DR(HLA-DR)are predictors of infection and prognosis in critically ill patients undergoing continuous renal replacement therapy(CRRT).Methods A total of 43 critically ill patients undergoing continuous veno-venous hemofiltration(CVVH)were recruited from the intensive care unit(ICU).Anti-coagulated blood was obtained at 1 day before and 4 days after undergoing CVVH,and plasma IL-10 level(enzyme linked immunosorbent assay)and HLA-DR expression(flow cytometry)were determined.Thirty healthy subjects were enrolled as controls.In addition,the correlation between IL-10 and acute physiology and chronic health evaluation Ⅱ(APACHE Ⅱ)score was assessed.Results ①Altogether,7 patients died among a total of 43 critically ill patients,the mortality was 16.3％.Eighteen patients had negative cultures during the study(group Ⅰ),and 19 patients had positive cultures(group Ⅱ),and in 6 patients positive bacterial culture appeared 72 hours after the beginning of the treatment(group Ⅲ).② The IL-10 level(ng/L)was higher in patients than in healthy subjects[23.46(46.71)vs.0.32(0.45),P＜0.01].Compared with group Ⅰ,the levels of IL-10 in group Ⅱ and Ⅲ were higher significantly[40.20(46.44),41.78(49.63)vs.7.33(21.05),both P＜0.05].Continuous observation revealed that IL-10 rapidly lowered in group Ⅰ after treatment[4.50(7.44)vs.7.33(21.05),P＜0.05],while there was no apparent change in patients of other two groups.It was found that IL-10 was significant positive correlation with the APACHE Ⅱ score(r=0.71,P＜0.01).③ H LA-DR was lower in patients than in healthy individuals[21.65％(25.62％)vs.90.39％(9.80％),P＜0.01].After CVVH,HLA-DR expression was obviously increased in group Ⅰ[64.95％(35.03％)vs.32.45％(45.03％),P＜0.01].However,there were no significant changes in the other two groups.The patients who died had persistent and extremely low HLA-DR expression.Conclusions ①A significant discriminative power of IL-10 levels in predicting disease severity was found among the patients receiving CRRT,and persistently high IL-10 level predicts poor prognosis.② Persistently low monocyte HLA-DR expression may indicate concomitant or impending infection in patients receiving CR RT.